Probs not needed. My cable/drum brake works fine as it is. I just wish the hydro was as good. It can lock up the rear easily. And it might fuck with the rear rotors. The Biot rear rotors are a funny thing. The handbrake "drum" part is seperate to the alloy hat. And seperate to the main rotor ring. The drum is steel and only covers approx half the handbrake pads. (To save weight) The other half of the arangement is the actual alloy hat.

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Doing it for all the wagons out there

Ah tru mine are second handies that doug had spare prob off a rally car and have had there day hehe

using the Perth-WRX mobile app

have you considered.......

Yeah. I have. Dont really want to go down that route, especially as im pretty committed to making this work. I honestly thought doing the dual calipers thing would be harder than just plumbing a handbrake master into the existing brake circuits.

Although in hindsight, it def would have been the better option. If i did it that way, i wouldnt have to touch the existing brakes. I could have used a small single master cylinder etc. But i wouldnt use 2 sets of brembos. Id use the biggest set of calipers i could get that take a 20mm wide disc. Doing 2 sets of brembos and id probably be in the same boat trying to make it work as i am now.

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Doing it for all the wagons out there

Just thought id throw this up here. This is supposely the piston and rotor sizes for the AP Subaru specific BBKs. Apparently these are the same as whats used on the homologated STi branded AP kit. Which is whats 'supposed' to be fitted with the AP STi handbrake master cylinder. (Yes, i know plenty of cars have the STi master, but dont have the $10k AP BBK) But the master cylinder was designed for use with these calipers in mind. I dont know how accurate it is as i havent confirmed the info. Someone put it up in my NASIOC thread.

What i find interesting is the rear caliper piston sizes. They are massive for a set of rears. They have nearly 3000mm^2 piston area. Which is like close to 1000 more than the Brembo rears and 700 more than the FHI/Sumitomo 2 pots. Rotor is a little bit smaller and thicker, but its not a massive differeence in the scheme of things. But rear piston area is mega big. It is by far the biggest rear BBK ive found specific for the Subaru. And that (if correct) confirms my initial suspicion that my rear calipers are too small compared to the master. The rear APs are like 50% bigger than the rear Brembos. If i could get my setup working another 50% better, im certain it could lock up under virtually any condition.





AP non-homologated caliper p/n:

CP6720-6S4L
CP6720-7S4L


(CP6720 = Ø34.9 x 2 / Ø41.3 x 2)

4590 mm^2 per front corner

CP6760-2S4L
CP6760-3S4L

(CP6760 = Ø27.0 x 2 / Ø34.0 x 2)

2959 mm^2 per rear corner

Rotor dimensions are as follows:

Front Tarmac = 355 mm dia., 32 mm thick
Front Gravel = 295 mm dia., 32 mm thick
Rear = 285 mm dia., 27 mm thick

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Doing it for all the wagons out there

^^^^But they don't come cheap!

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No Subarus currently owned

Are you going to change the plumbing to how people have suggested before replacing everything else?

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Bye bye betty blue. Hello F6.

Bram, I guess the thing to remember (and I keep harking back to it) is that the setup you bought from me worked perfectly on an MY06 STI tarmac rally car fitted with Brembo brakes and PMU pads...the only difference is that the tarmac car did not have ABS....

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No Subarus currently owned

My plan so far is.

1. New pads. Already ordered. I chose this as its an easy and relatively cheap test. (Ordered from UK because over 20% cheaper delivered than AU prices.

2. RE-route the plumbing and bypass the ABS. (Basically make it like Grp N.)

3. If i still cant get it to a point that Im happy with, then i think ill add the cable linkage.

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Doing it for all the wagons out there

Yeah. I understand that.

Which is why im going to try and address those 2 differences next. (First pads because its easier than re plumbing the entire cars brake system.) Then if that doesnt work, then ill have look at changing the plumbing.

I just found it interesting that the STi AP rears were considerably larger than the brembos. And not like a little bit bigger, like a whole fucking lot bigger.

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Doing it for all the wagons out there